Class Trait Survey
Every human is unique. And yet, when scientists examine the genetic material that makes us who we are, they find that every human's DNA differs by only 0.1 percent! Some of these differences are inherited traits passed down from parents and ancestors through genes.
Different forms of the same gene are called alleles. Some are dominant, and some are recessive. When a dominant and Page 292 | Top of Articlea recessive allele are present, only the dominant allele is expressed. Polydactyly, or having extra fingers or toes, is a dominant allele. Someone who has the alleles for six fingers on each hand (dominant) and five fingers on each hand (recessive) will have six fingers on each hand. People who have five fingers on each hand do not have the dominant allele; they have only the recessive alleles.
While many of our traits are genetic, other traits are acquired. We get them from our experience rather than from our genetic code. For example, the ability to play a musical instrument is an acquired trait. Acquired traits cannot be passed down to offspring through genetic code, though some may be passed down through education or learned behaviors.
You will work in a three- or fourperson team to examine select inherited and acquired traits of yourself and your fellow team members.
- Pens or markers
- Graph paper
- Pocket mirror
Your challenge is to gather information about specific inherited and acquired traits of all members of your group, including yourself. You will record your findings on the Genetic Trait Recording Sheet (located in the Appendix) and calculate the frequency of each trait.
- Look at the list of traits on the Genetic Trait Recording Sheet. Take turns examining your team members, or use a mirror to examine yourself, for evidence of each trait. Record data for each group member.
- Calculate the frequency of each trait. The formula for calculating frequency can be found in the Help Guide below.
- Use a calculator to check your calculations.Page 295 | Top of Article
- Using graph paper, make a bar graph of the data. Label the x-axis “Genetic Traits” and the y-axis “Trait Frequency (% Students).” For each trait, create two different- colored bars: one for dominant alleles and one for recessive alleles.
- Determine which alleles were the most common in your group and which were the least common. Then identify any traits that were highly skewed—that is, any that showed a large difference between the frequencies for dominant and recessive alleles.
- Write a brief paragraph summarizing your findings.
- Proofread your paragraph and correct any spelling and grammar errors.
The success of your survey results will depend on the care with which you observed and recorded your information, as well as the accuracy of your calculations. Your paragraph should demonstrate your understanding of the survey results and should be free of errors.
See Appendix for Genetic Trait Recording Sheet .
Now that you have surveyed your classroom, give the survey to your family to see how your traits compare to those of your family members. You might also survey your extended family to see how traits are distributed through your family tree.